Cuar. 1, § 1.] PLAN OF THIS DISSERTATION. 803 
( 
a AR i But the extended domain of the science of the Mathematics. But an equally sound reason might 
alaty “¢ Jast hundred years enhances vastly the difficulty of the be found in my consciousness of inadequacy to un- 
materials, subjects succinctly handled as one by Mr Playfair. 
The mechanical and experimental sciences alone con- 
stitute a body of knowledge so largethat it is arespon- 
sibility sufficient for one person to attempt to grasp 
them all, and to set forth in order the steps of pro- 
gress and improvement which have been so rapid, and 
even so startling. Since some of these have scarcely 
as yet been historically digested, and the broad 
features of contemporary discovery have not been 
gradually separated by the judgment of an impartial 
posterity from those slighter though praiseworthy 
details, which lapse of time and advance of know- 
ledge will throw into the shadows of distance,—this 
difficult and most laborious task falls principally 
upon the reviewer. The length and breadth of the 
subject of Natural Philosophy, and the cumbrous 
and scattered depositories of knowledge in which 
its records must be sought, combine to render not 
only the undertaking an arduous one, but the 
result of it a good deal more bulky than might be 
desired, or than was easily possible, in dealing with 
the glorious, but compact, history of Newton’s age. 
It might be compared to the difference between writ- 
ing a history of the Jews or Romans and that of the 
whole of modern Europe. 
dertake, whatever had been the dimensions of my 
work, a threefold scheme of such magnitude and 
difficulty. I do not think that any one person could 
“be found to treat the whole as it ought to be treated, 
and I am certain that I am not that person. 
One attempt—a bold and successful one—has 
been made, in our own day, 
three departments,—I mean the History and the 
Philosophy of the Inductive Sciences. 
philosopher of wonderful versatility, industry, and 
power has erected a permanent monument to his 
reputation in a voluminous work bearing the pre- 
ceding title.1 A slight inspection of that work will 
show how impracticable and self-destructive a plan it 
would have been to attempt anything like a syste- 
matic abridgment of such a mass of facts and specu- 
lations within our present limits. Mr J. Stuart Mill 
has also published a work bearing on the origin of 
our scientific knowledge, diametrically opposed in 
principle to the preceding one, yet marked by great 
ability.2 Such disquisitions belong more properly 
to the philosophy of the human mind than of phy- 
sies. After all, be it remembered that whatever has 
been learnt or discussed concerning the means of 
arriving at truth in Natural Science, it is not pre- 
as.) The mere magnitude of the undertaking, then, tended that we have recently become possessed of 
eel might well excuse me from entering upon the cog- any canons or rules of discovery superseding those 
nate, but exceedingly distinct, subjects of the Logic 
of Inductive Discovery and the progress of the Pure 
fundamental principles of observation and experi- 
ment so well laid down by Bacon, and practised both 
to unite t Writings of 
un wo of the DeWhevall 
~ and Mr Stu- 
An English art Mill. 
the present volume will bear an enduring testimony. Playfair’s original contributions to science were not so marked and consi- Character 
derable as to justify me in including his name in the comparatively brief catalogue of discoverers chronicled in the succeeding of Professor 
pages; but his efforts are, nevertheless, deserving of notice, and indirectly were perhaps hardly less beneficial. He was a most Playfair. 
= 
patient and admiring student of the greatest mathematical writers of his time, and, when we consider the singularly backward 
state of that science in Great Britain about the end of the last and commencement of the present century, it was of no slight im- 
portance to find a man placed in the position of a public instructor able and willing to direct attention to the splendid achieve- 
ments of the continental mathematicians. By his lectures both on Mathematics and Natural Philosophy—by his luminous articles 
in the Edinburgh Review—by some of his original papers in the Zransactions of the Royal Society of Edinburgh—he contributed 
to this useful end, and would have done so still farther had he been enabled to complete the Dissertation which he so ably com- 
menced. He had an excellent mathematical capacity, and mathematical taste, rather than power. His explanations, even of 
matters of inherent difficulty, are perspicuous and popular, qualities possessed by few of his contemppraries. His style has been 
pronounced by the highest authorities to be a model of clearness and eloquence. He was extensively read in subjects of meta- 
physics and morals, as well as of pure science ; and by a combination of talent rare, I am inclined to say, in a high degree, his 
taste, though eminently mathematical, was also directed, with signal success (at first through his intimate friendship for Dr Hutton), 
to the very opposite studies of Geology and Physical Geography, which may be said to have been the subjects of his predilection 
_ during the last twenty years of his life. Nor were these labours of the closet merely ; he was far more intimately versed in the 
mineral structure of the earth, from observation, than any except a few professed geologists ; and he exceeded them all in the 
ability with which he expounded and maintained the striking doctrines of the Huttonian theory. Though professedly the “illus- 
trator” of the principles specifically but obscurely laid down by Hutton, he certainly added much of his own. There is no rea- 
son to doubt that Playfair first apprehended the moving power of glaciers as geological agents in modifying the surface of Alpine 
countries, a matter which has of late been so earnestly discussed by the ablest geologists. 
What adds to the singularity of tne combination of tastes and talents to which I have referred is, that he appears to have 
had the slightest possible taste for that art of experiment which he eloquently advocated, with Bacon, as the grand distinction of 
modern science. I may be wrong in stating it broadly, but I do not now recollect a single experimental novelty, much less dis- 
covery, which we owe to Playfair, I mean in the department of Natugal Philosophy; for we cannot include barometrical mea- 
surements under this head, of which, indeed, it was the mathematical theory, and not the application to practice, which chiefly 
occupied him. The same was the casein Astronomy, which, of the mechanical sciences, interested him most. In two capacities he 
will be remembered,—first, as the able, eloquent, and generally impartial and accurate Historian of Science; secondly, as the 
promoter, to so great a degree as to be considered a second founder, of modern Dynamical Geology. He was much beloved in 
private life, and was singularly free from the tendency to carping criticism and personal prejudices sometimes, unfortunately, 
found in men of letters. He was the intimate associate of Jeffrey and the other founders of the Edinburgh Review. 
His character has been drawn in three words by Sir James Mackintosh, and as happily contrasted with that of his illustrious 
friend :—“..... Playfair and Jeffrey; the first a person very remarkable for understanding, calmness, and simplicity, the 
second more lively, fertile, and brilliant than any Scotchman of letters”’ (Life of Sir James Mackintosh, ii. 251). 
1 Whewell’s History and Philosophy of the Inductive Sciences, 5 vols, 8vo. 2 Mill’s Logic, 2 vols. Svo. 
